US warns of 'dangerous' heat-wave
US authorities have warned of a potentially deadly heat-wave passing over the middle of the country.
In swathes of the Mid-west the heat index - how the weather feels - was due to top 38C (100F), officials said.
The heat and humidity made the air in Newton in the US state of Iowa feel 52C (126F), weather reports said.
The US National Weather Service warned of "the most significant heat-wave the region has experienced in at least the last five years".
The "heat dome" of high air pressure, high temperatures and high humidity was expected to expand from the central Mid-western core of the US outward, reaching the eastern US states by mid-week.
"The combination of hot temperatures and high humidity will combine to create a dangerous situation in which heat illnesses are likely," the National Weather Service warned.
Afflicted states included Illinois, Wisconsin, Minnesota, Iowa, Missouri, Kansas, Nebraska, Oklahoma, and South and North Dakota.
Authorities warned residents under the heat dome to drink plenty of fluids, stay in air conditioned spaces, out of the sun and to check on relatives and neighbours.